Nether accessed in 1.16.0.51, 1.16.0.55 and 1.16.0.57 update cannot be accessed in the latest beta, trying to access the nether results in the game crashing. 

*What I expected to happen was... *

Nether accessed in any version of the game should not crash the game when the player tries to access it in the latest version. The changes should be made in the unloaded parts of the nether. 

What actually happened was

Accessing the nether in the latest version crashes the game if you already accesed it in the previous version. 

Steps to reproduce

1) Create a nether portal in 1.16.0.51 or any previous version. 

2)Use the nether portal, ie. access the nether. 

3)In 1.16.0.58 open the world and access the nether. 

Please fix this problem, it hinders the gameplay greatly.